Craft for embarking/landing on unequipped shorelines

ABSTRACT

Craft for embarking/landing loads, particularly personnel and/or vehicles, on unequipped shorelines, of the catamaran type, comprising:  
     a mobile platform which is provided between two lateral hulls of the said catamaran, this platform being produced in the form of a watertight box, the upper part of which supports the loads by forming a running surface, and a deployable ramp being provided at each end of the said platform, the latter and the said ramps in the deployed position constituting a loading corridor of uniform width equal to the spacing between the two hulls, and  
     mechanisms to make it possible to vary the relative position of the mobile platform and of the hulls of the catamaran so that the craft floats either via the catamaran hulls alone or via the entire area of the said platform and of the hulls of the said catamaran.

[0001] The present invention relates to a craft for quickly landing/embarking loads, particularly those such as personnel and/or civilian or military vehicles, on unequipped shorelines while at the same time allowing swift transit, for example between a ship at sea and the shore.

[0002] At the present time, landings from ship to beach are carried out using craft of the landing craft type, using hovercraft or using helicopters.

[0003] A landing ship of the landing craft type has a shallow draught allowing for landings on beaches of gentle gradient, but has the drawback of low speed due to its shape and limited capability for movement as a result of its shallow draught and the fact that it is rather top heavy.

[0004] A high-speed ship of necessity has a deep draught which prevents it from getting in close to a gentle sloping beach.

[0005] Finally, the use of helicopters for landing vehicles from a ship entails the use of specialist ships equipped with a platform and, what is more, their payload is limited and this is a major drawback when the issue is one of landing armoured vehicles, particularly tanks.

[0006] The present invention has set itself the object of producing a landing craft which is characterized, on the one hand, by a high transit speed and, on the other hand, by its ability to land loads onto gentle sloping beaches.

[0007] In consequence, the subject of this invention is a craft for embarking/landing loads, particularly personnel and/or vehicles, on unequipped shorelines, of the catamaran type, characterized in that:

[0008] provided between the two lateral hulls of the said catamaran is a mobile platform, this platform being produced in the form of a watertight box, the upper part of which supports the loads by forming a running surface, and a deployable ramp being provided at each end of the said platform, the latter and the said ramps in the deployed position constituting a loading corridor of uniform width equal to the spacing between the two hulls, and

[0009] mechanisms are provided to make it possible to vary the relative position of the said mobile platform and of the said hulls of the catamaran so that the craft floats either via the catamaran hulls alone or via the entire area of the said platform and of the said hulls.

[0010] According to one embodiment of the invention, the said mechanisms are produced as follows:

[0011] the two lateral hulls of the said catamaran are connected at the upper part and at each of their respective ends by beams and

[0012] there are lifting means which allow the said platform to be brought respectively into the raised or transit position and into the lowered or embarking/landing position in which the said platform provides additional buoyancy to allow the draught of the craft to be reduced.

[0013] According to the present invention, the two hulls may also be connected, at the bottom part, by profiled crossmembers or beams, preferably in the shape of wings, the box constituting the said mobile platform being produced in such a way that in the lowered position the said crossmembers nest into the underside of the said box. According to the present invention, mobile flaps may also be arranged in the said profiled crossmembers so as to adjust the trim of the moving craft according to the centre of mass and the sea conditions, it also being possible for these flaps to be used as stabilizers for high-speed transit in rough seas.

[0014] According to another feature of the present invention, the means of lifting the platform are of the type with mechanical guidance by articulated arms, lockable in the raised and lowered positions and actuatable in both directions.

[0015] According to the invention, the means of guiding the mobile platform may be produced in the form of a mechanical guide system on rails, or using chains or any other appropriate system.

[0016] According to the invention, the platform may be locked in the raised or lowered position using a system of pins or brackets, possibly retractable ones, or mechanical latches.

[0017] Other features and advantages of the present invention will become apparent from the description given hereinafter with reference to the appended drawings which illustrate one embodiment thereof which is entirely nonlimiting. In the drawings:

[0018]FIGS. 1 and 2 are diagrammatic elevations depicting, respectively, the craft according to the present invention in the transit position and in the landing position;

[0019]FIGS. 3 and 4 depict, in perspective, the craft that is the subject of the invention, respectively in the transit position and in the landing position,

[0020]FIG. 5 is a perspective view similar to FIGS. 3 and 4 depicting the craft without the mobile platform, and

[0021]FIG. 6 is a front view of the craft that is the subject of the invention.

[0022] Referring to the drawings, it may be seen that the craft that is the subject of the present invention is in the form of a catamaran, the two hulls 10 and 12 of which are connected at each of their ends and at the upper part by beams 11 and 13. This then produces a structure that allows the assembly to be kept rigid independently of the mobile platform 15 described hereinafter. In the exemplary embodiment depicted in the drawings, the two hulls 11 and 12 are also connected, at the bottom part and at each of their respective ends, by profiled bottom crossmembers 16 and 17, in the region of the profiled keel of the hulls 10 and 12, these crossmembers 16 and 17 preferably being in the shape of wings so as to develop partial upthrust effects ensuring relatively high speeds. These crossmembers 16 and 17 may be fitted with mobile flaps 21 and can be seen in FIG. 6 so that the trim of the moving craft can be adjusted according to the centre of mass and the sea conditions. These flaps may also be used as stabilizers for high-speed transit, particularly in rough seas.

[0023] The mobile platform 15, which is produced in the form of a watertight box, is positioned between the two hulls 10 and 12 and consists of a watertight box, the upper part of which forms a running surface supporting the load depicted in FIGS. 1 to 5 as armoured vehicles and in FIG. 6 as trucks. At each of the ends of the mobile platform 15 there is a deployable ramp 18, 19 respectively, so that the platform 15 and the ramps 18, 19 constitute a loading corridor of uniform width equal to the spacing between the two hulls 10 and 12 (see FIG. 4). As a preference, the ramps are of the fold-out double-fold type. In the folded position they protect the loads transported by the craft from the waves and from the spray (see FIG. 3).

[0024] When the hulls 10 and 12 are connected at the bottom part by crossmembers such as 16 and 17 (FIG. 5), the latter, when the mobile platform 15 is in the lowered position, nest in the underside of the platform, which protects them at the time of “beaching” (see FIG. 2).

[0025] The craft also comprises lifting means depicted diagrammatically as 20 and 20′ in the figures and which are designed to allow the platform 15 to be brought respectively into the raised or transit position and into the lowered or landing/embarking position, in which position the box constituting the platform provides additional buoyancy allowing the draught to be reduced to provide access to the shore.

[0026] According to one exemplary embodiment of these lifting means, these may be of the type with mechanical guidance by articulated arms, lockable in the raised and lowered positions and actuatable in both directions. This two-way actuation may be achieved, for example, using double-acting rams or using a system of the worm-and-rack type. The movements of the platform are controlled from the bridge.

[0027] In the exemplary embodiment illustrated in FIG. 6, 24 has been used to depict the system for guiding the mobile platform 5, this system possibly consisting of a mechanical guide system on rails, or of articulated arms as mentioned hereinabove, or alternatively of chains or any other appropriate device. This same FIG. 6 diagrammatically depicts the devices for locking the mobile platform 15 in the raised position 22 or lowered position 23. These devices may be produced in the form of pins or brackets, possibly retractable ones, or mechanical latches or any other appropriate system.

[0028] According to the invention, the aforementioned two-way actuation depicted diagrammatically at 25 in FIG. 6 may be produced in the form of double-acting rams acting directly on the mobile platform 15 or acting via articulated arms mentioned hereinabove, or alternatively via racks or winches operating cables or alternatively still using geared motor units driving chains. It is also possible, to this end, to use a combination of the aforementioned systems or any other means of providing power in two directions.

[0029] Propulsion is preferably provided by hydrojets with directional nozzles and reverser spouts to provide excellent manoeuvrability and very short stopping distances. These hydrojets which are not depicted in the drawings are arranged symmetrically in the two lateral hulls 10 and 12, appreciably above the bottom thereof. It is also possible to provide lateral thrusters at the front of the hulls to make lateral control of the craft easier.

[0030] In transit (FIGS. 1 and 3), the craft according to the invention has a configuration for sailing on its two profiled hulls 10 and 12 allowing high speed even in choppy seas. The load is carried on the platform 15 positioned at the top of the hulls and is protected by the bow and stern ramps 18 and 19.

[0031] On approaching the beach (FIGS. 2 and 4) the platform 15 is lowered to the lower part of the hulls 10 and 12 and in this position it provides the craft with additional buoyancy allowing its draught to be reduced to a shallow enough value to allow it to access the edge of the beach, the ramp such as 18 then being deployed to allow the personnel and vehicles to land in the conventional way.

[0032] As will be understood, the platform 15 and its ramps 18 and 19 constitute a loading corridor of uniform width suited to equipment being arranged in a line in the raft of landing craft transport.

[0033] The device that is the subject of the invention can be used for any high-speed transport of people, equipment, vehicles, by sea or river such as, for example:

[0034] for transporting environmental protection equipment to allow civil protection equipment to be brought to any point along a coastline or along the banks of a river;

[0035] for transportation for humanitarian purposes along an unequipped shoreline;

[0036] for transportation and landing of military equipment and personnel;

[0037] for river or sea transportation without port facilities or with limited or very shallow facilities;

[0038] for maritime transportation of products from a ship in the high seas to a bank or shoreline not equipped with port facilities or equipped with very shallow facilities.

[0039] The advantages afforded by the craft that is the subject of the invention are, in particular, as follows:

[0040] significant transit speed capability even in choppy seas when the platform is in the raised position;

[0041] significant reduction in draught allowing an approach very close to the edge of a beach, with the loading platform in the lowered position with its running surface above water level, the presence of the front ramp reducing still further the amount of water to be negotiated;

[0042] excellent manoeuvrability in the transit position and of the landing position;

[0043] a wide buoyancy surface in “beaching” mode to give high sensitivity to the centre of mass and allow a great deal of flexibility in the way the load is distributed;

[0044] the possibility of providing flaps such as 21 in the profiled lower crossmembers such as 16 and 17, these flaps being profiled in such a way as to adjust the trim of the moving craft according to the centre of mass and the sea conditions, and these flaps being usable as stabilizers.

[0045] It must remain clearly understood that the present invention is not restricted to the embodiments described and/or mentioned hereinabove by way of nonlimiting examples but that it encompasses all alternative forms thereof. 

1. Craft for embarking/landing loads, particularly personnel and/or vehicles, on unequipped shorelines, of the catamaran type, comprising: a mobile platform which is provided between two lateral hulls of the said catamaran, this platform being produced in the form of a watertight box, the upper part of which supports the loads by forming a running surface, and a deployable ramp being provided at each end of the said platform, the latter and the said ramps in the deployed position constituting a loading corridor of uniform width equal to the spacing between the two hulls, and mechanisms to make it possible to vary the relative position of the mobile platform and of the hulls of the catamaran so that the craft floats either via the catamaran hulls alone or via the entire area of the said platform and of the hulls of the said catamaran.
 2. Craft according to claim 1, wherein the two lateral hulls of the said catamaran are connected at the upper part and at each of their respective ends by beams and lifting means are provided for allowing the said platform to be brought respectively into the raised or transit position and into the lowered or embarking/landing position in which the said platform provides additional buoyancy to allow the draught of the craft to be reduced.
 3. Craft according to claim 1, wherein the hulls are also connected at the bottom part by wing-shaped crossmembers, the box constituting the said mobile platform being produced in such a way that in the lowered position the said crossmembers nest into the underside of the said box.
 4. Craft according to claim 3, wherein the said crossmembers are fitted with mobile profiled flaps. 